Amoi Power Bank Test :

Purchased off Ebay

Yes , it does say 10400mAh , but I was rather skeptical ! For all I
know the actual battery capacity may very well be 10400mAh and the power
bank is simply horribly inefficient . Or perhaps the capacity claims are
very optimistic ? Either way the first thing I did was fully
charge the Power Bank . What is nice about this one is the digital read
out giving you a % for capacity read out . As received it was showing
84% . So once the power bank stopped accepting a charge and was
reporting 100% capacity :

Discharge test :

I used one of my action cams to see
how much power the bank would return to the user . I removed the action
cams battery to eliminate it as a consideration and inserted a Charge
Doctor in line with the cam to record mAh used . The cam was
pulling 0.24 - 0.3 amp ( Varied ) and I left it on all night to see how
much power the bank had to offer . Starting @ 6.30pm the cam ran
until around 11am the next morning .. At 10.15am the Bank reported 12%
capacity remaining and some 4548mAh used by the action cam .

After returning from shopping the cam had stopped and the Power Bank
was reporting 0% capacity with some 5060mAh drawn from the 10400mAh Bank
. To put that in perspective , the Bank has 4 x 18650 and each battery
returned the user 1265mAh .

Charge time :

I started recharging the Power Bank about 11.30 am @ 1 amp ..

1.30pm = 12%

3.30pm = 17%

5.30pm = 24%

8pm = 59%

9.30pm = 84%

10.30pm = 96%

11.30pm = 99%

00.30am to 1am = 100%

So with a 1A USB charger ( charging @ 1A to begin with ) it has taken
some 13 hours to recharge the powerbank . And with the charge rate
between 1A and 0.75A for most of the charge cycle , 8 to 9 hours . So I
can only conclude that a lot more energy went in than came out and that
possibly the voltage boosting circuit is horribly inefficient .

Conclusion :

What we have is a 5000mAh ( to the user ) powerbank
that is painfully slow to recharge once depleted that has a flashlight
built in ( oh I tried very hard to find a powerbank without a flashlight
built in ) that has two USB ports ( power out ) and a digital display
showing capacity as % . I don't have any USB adapters capable of more
than 1A and the bad news for most of you is that a lot of them (USB
adapters ) will only do 0.5A or less ( That might mean like 26 hours to
charge ) .

Was I expecting more for $15 ozzi bananas ? , not really . I got
pretty much what I expected for available mAh to the user ( What you get
from the bank ) . I did not how ever expect such long charge time ,
that was a little bit of a surprise . The action cam ran for a little
over 16 hours just in case you are interested in 2FPS mode . I am
not sure I won't a whole bunch of powerbanks , but I may try another in
2017 .